Conditional Payment Smart Contract

A robust escrow system built on the Stacks blockchain using Clarity that enables secure conditional payments between parties with built-in dispute resolution.

Overview

This smart contract implements a trustless escrow service where payments are held until predefined conditions are met. It supports multi-party transactions with optional arbitration and automatic refunds for expired payments.

Key Features

• Conditional Escrow: Funds locked until cryptographic proof of condition fulfillment
• Multi-Party Support: Payer, payee, and optional arbiter roles
• Timeout Protection: Automatic refunds after expiration
• Dispute Resolution: Arbiter-mediated conflict resolution
• Fee System: Configurable contract fees (default 0.5%)
• Security: Comprehensive input validation and access controls

Core Functions

Payment Creation

(create-payment payee amount condition-hash timeout-blocks arbiter)

Creates a new conditional payment with specified terms. Funds are immediately escrowed.

Condition Verification

(verify-condition payment-id proof-data)

Verifies that provided proof matches the original condition hash using SHA256.

Payment Release

(release-payment payment-id)

Releases escrowed funds to payee after conditions are verified. Deducts contract fee.

Refund Processing

(refund-payment payment-id)

Returns funds to payer if payment expired or authorized by arbiter.

Dispute Management

(dispute-payment payment-id)

Flags payment as disputed, requiring arbiter intervention.

Usage Example

1. Create Payment: Payer creates payment with condition hash and timeout
2. Verify Condition: Any authorized party submits proof data
3. Release Payment: Once verified, funds transfer to payee minus fees
4. Handle Disputes: Arbiter can resolve conflicts or force refunds

Security Features

• Input Validation: All user inputs validated before processing
• Access Controls: Only authorized parties can perform actions
• Reentrancy Protection: State changes before external calls
• Principal Validation: Prevents invalid or self-referencing addresses

Error Codes

• u100: Unauthorized access
• u101: Payment not found
• u103: Insufficient funds
• u104: Payment expired
• u106: Conditions not met
• u108: Invalid input parameters

Deployment

Deploy using Clarinet or Stacks CLI. Set appropriate contract owner and initial fee structure before mainnet deployment.

This contract provides a secure foundation for conditional payments with comprehensive error handling and dispute resolution mechanisms built for production use.